A three-dimensional printing solid freeform fabrication (SFF) system may utilize one or more liquids that the system solidifies so as to fabricate successive layers of a solid product in a desired form. The liquid may be, for example, a photocurable liquid that is polymerized and solidified through exposure to radiation, such as ultraviolet (UV) radiation. Such a system may produce fluid waste as a byproduct of the fabrication process. It may not be desirable to store the waste in its liquid form, and laws or regulations may prohibit this. It may not be desirable to dispose of such waste by using such standard methods as a sewerage system or a municipal waste removal service, and laws or regulations may prohibit this as well. It may be easier to dispose of or handle the waste when solidified.
Systems for removing and accumulating waste material from an SFF system have been described previously. A system in which waste material from an SFF system is stored in an accumulator tank has been described previously. In the described system, when the accumulator tank is filled, the contents of the accumulator tank are emptied into removable receptacle, such as a disposable polypropylene bag. When the removable receptacle is filled with fluid waste, a user may remove the removable receptacle and replace it with another. The accumulator tank serves as a buffer between the SFF system and the removable receptacle, so that the removable receptacle may be removed while the SFF system is in use.
Other systems have been described to overcome a problem of fluid waste that may become too viscous to flow, or that may even solidify, when allowed to cool to room temperature. With such fluid waste, an accumulator tank, as well as all tubing that brings waste to the accumulator tank, may need to be heated. When the removable receptacle is not heated, fluid waste emptied into it may solidify prematurely and unevenly, rendering the receptacle difficult to fill. Therefore, a variation of the above waste disposal system has also been described. The variation attempts to overcome the problem of uneven solidification in the removable receptacle by allowing heated fluid waste from the SFF system to flow directly into the removable receptacle. A source of radiant heat heats the fluid waste that has accumulated in the removable receptacle. The radiant heat maintains the upper layer of the accumulated fluid waste in a liquid state. Prior to removing and replacing the removable receptacle, the waste in the receptacle is allowed to cool and to solidify or gel. However, the receptacle cannot be removed or replaced while the system is operating.
In the above systems the waste accumulates for the most part in liquid form until it is removed by, or is about to be removed by, a human operator. Therefore, there exists the possibility of spillage or leakage of the fluid waste during handling.